Cylinder for engines of the opposed piston type



Jap. 24,1939. R. PATERAs PESCARA 2,144,706

CYLINDER FOR ENGINES OF THE OPPOSED PISTON TYPE Filed March 26, 193e 2vsheets-sheet 1 A y? g2 J 5a (f1.

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CYLINDER FOR ENGINES OF THE 'OPPOSED PISTON TYPE Filed March 26, 1936y 2Sheets-Sheet 2 lill!! MJF-Mil r //j /Q INVENTOR l RAUL PATERAS PESCARA(af n.775 ula/jana?? ATTORNEYS Patented Jan. 24, 1939 CYLINDER FOREGINESfOF THE OPPOSED' PISTON TYPE Raul Pateras Pescara, Paris, France,assignor of one-tenth to Socit Etudes et de Participations, Eau,

Gaz, Electricite, Energie, S. A.

Application March 26,'1936,Serial No. I71,036 In France March 30, 1935 4Claims.

This invention relates to the design and construction of the cylindersin heat engines of the opposed-piston type, that is, engines comprisingone or more pairs of pistons moving in opposite directions within acommon working cylinder. It concerns more particularly (because thiscase appears to oier the most favorable field of application), but notexclusively, cylinders of engines of the above type which are subjectedto unusually high pressures.

The principal aim of the invention is to adapt such cylinders moreclosely than has heretofore been achieved to the most exactingrequirements of practical service.

The principal object of the invention is to build cylinders of the abovetype in at least three distinct longitudinal and co-axial sections, thecentral section forming a part of the combustion chamber, and theadjacent and co-axial sections being designed to insure the satisfactorymechanical and thermal operation of the pistons, as kregards frictionand cooling.

Aside from this principal object, the invention has certainother-objects which are preferably associated and which will be morespecifically described herebelow, as for example:

A second arrangement wherein the different cylinder sections areassembled by means of elastic connections adapted to take up differencesin the heat expansion of the separate cylinder sections;

A third arrangement wherein the central section is cooled independently,thus allowing the use of said section as a means of generating steam;and

A fourth arrangement wherein a pre-combustion or ignition chamber isformed within the thickness of the wall of the central section, in whichchamber combustion of the fuel is started and at least partiallycompleted.

.The invention also extends to all applications of the above'designs,'together with their structural details, to heat enginesembodying cylinders of these designs and to machines and/or allinstallations embodying such engines and/or cylinders.

Other objects and advantages of the invention l' will appear in thecourse of the detailed description now to be given with reference to theaccompanying drawings, which are given by way of example only. In thesedrawings:

Fig. 1 shows in longitudinal cross section an A engine cylinderembodying this invention.

Fig. 2 is an enlarged cross section of a modification of the centralelement I shown in Fig. 1.

(Cl. 12S-51) Figs. 3 and 4 show large-scale details of two modied meansof connecting the diiierent cylinder sections together.

Fig. 5 shows, in longitudinal cross-section, a

portion of a cylinder embodying a modified form 5 of the invention.

Fig. 6 shows, in longitudinal cross-section, a portion of a cylinderembodying a further form of execution of the inventio In accordance withtheinvention, and more lo Instead of building the cylinder as one intel5gral tubular member, said cylinder is divided into at least threelongitudinal sections comprising one central section I enclosing aportion of the combustion chamber, and associated on either side withadjacent co-axial cylinder sections 21 and 22.

The central section I .may be composed either of a ring which mayadvantageously b e thickwalled and made of a high-resistance materialsuch as steel, or of a plurality of concentric rings la, Ib, Ic (seeFig. 2) shrunk upon each other, in order to insure greater mechanicalstrength than a single ring of the same thickness, said concentric ringsbeing made of the same high resistance material, such as steel, or ofdifferent 30 materials of suitable composition. For example. theinnermost ring Ia may be made of a mate- Arial resistant to corrosion,one or more intermediate rings Ib of a heat-insulating material, and theouter ring or rings I of a highly resistant material such as steel.

The adjacent cylinder sections 21 and 2 may be formed of co-axialcylinders of equal bore, said cylinders being composed of a. material,such as special grades of cast iron, having a good friction coeilicient.l

Thethree cylinder sections lf2l and'fi!2 may be assembled by anysuitable means. For example, they may be simply provided at theirextremities with male and female screw threads. and screwed together; orthey may be assembled by meansof bolts or studs 4.

In one of my preferred designs, the different cylinder sections I, 21and 22 may be accurately centered tothe common axis b'y means ofcarefully machined bearing surfaces 5 ground to a tight though slidingfit, as in Figs. Ito 5.

The transmission of heat from the central section I to the adjacentsections 21 and 22 lmay advantageously be reduced by reducing to a 55minimum the area of all contact surfaces between the assembled parts andby leaving a suitable clearance between such surfaces as 1 through whichpass the connecting bolts 4. Materials of low heat conductivity such asat 6B (Fig. may also be interposed between said surfaces.

Under certain conditions, it may be advisable to'reduce the rate of heatdissipation from central cylinder section I which forms the combustionchamber. 'I'his may be achieved as shown in Figs. 1 to 4, by leavingthis section uncooled, and/or by incorporating in its constructionmaterials of low heat-conductivity. If necessary, the temperature riseof the cylinder walls in the central section may be reduced by formingthe inner portions of said cylinder of heat-insulating material, or inany other appropriate manner.

In cases wherein the different cylinder sections are subjected todifferent degrees of heat expansion, elastic' connecting means may beprovided to assemble said cylinder sections which allow each of saidcylinder sections to expand independently of the adjacent sections.

Said elastic connecting means may be associated with expansible sealingmeans 61, Fig. 1, such as plastic washers, which take up the dimensionalvariations of the adjacent cylinder sections and thus insure tightjoints between said sections.

The working cylinder may be cooled by means of a common water jacket, orby any other suitable cooling means; or each cylinder section may beprovided with separate cooling means. In. certain circumstances, it maybe advisable not to cool the central cylinder portion, as shown in Figs.1 to 4. In these cases, cylinder sections 21 and 22 are provided withseparate water jackets Il and 82, preferably interconnected by suitableconnections as shown at 9 in Fig. 3 and Ii in Fig. 4.

Under certain conditions, central cylinder section l may be providedwith a separate water jacket I0, asin Fig. 5, and the heat evacuatedfrom that section used to vaporize the cooling water,

, thus form'ing a steam generator.

On the contrary, when central cylinder section i is made of a materialhighly resistant to corrosion and high temperatures, it may beadvantageous not to cool that section, so as to avoid unnecessary lossof heat during the combustion of the fuel.

In this case, advantage may be taken of the aree-,voe

high temperature or this central cylinder sec tion to combine with it anignition and/or precombustion chamber, as i2, Fig. 6, in which 'the fuelis injected.

In general, I build the central cylinder section I of a material ofhigher mechanical strength than that used for the adjacent sections 21and 22, and, as described above, in one solid ring, or in the form ofconcentric rings shrunk upon each other. The reason for thisconstruction lies in the extremely high pressures which may be attainedeither accidentally or in regular or overload operation, in engines ofthis type, and particularly in generators of gas under pressure of thefree opposed-piston type, in which the pistons may at times come veryclose together.

The above described embodiments of my invention refer to asingle-cylinder engine oi the opposed-piston type. But it is evidentthat the same i onstruction may be applied to multi-cylinder engines ofthis type.

It is understood that the above description and the attached drawingsare submitted by way of example only, and that my invention is, notlimited to any of the embodiments described, and extends to all variantsthereof.

I claim:

l. A combustion engine comprising a cylinder, oppositely working pistonsslidabie in said cylinder, at least the inner wall of said cylindercomprising three parts, the central part being formed of a materialwhich is resistant to mechanical stresses and corrosion and forming thecombustion chamber, the two lateral parts forming the guiding surfacesfor said oppositely working pistons, means for cooling said lateralparts to a greater extent than said central part and means for reducingheat transmission from the central part to said lateral parts.

2. In an engine according to claim 1, said means cooling said lateralparts only.

3. In an engine according to claim 1, said means comprising a member onsaid central part containing steam for cooling said central part, andmembers on said lateral parts containing water for cooling said lateralparts.

4. In an engine according to claim l, means for securing together saidthree parts, and means for compensating the difference in the expansionof the individual parts.

RAUL PATERAS PESCARA.

